Design Of Focus Image Plane Positioning In Excimer Laser Micromachining And Z-Axis Tracking System

With the development of science and technology, laser processing technology as an advanced manufacturing technology has played an irreplaceable role in areas of industry, aerospace, machinery manufacturing and medical treatment, etc., and it also plays an important role in improving the product quality and achieving automation. The excimer laser micromachining technology has been widely studied and used for its high imaging resolution, small heat effect, small absorption coefficient and high power density, such as surface polishing, biochip production and graphics processing using the excimer laser. In the excimer laser micromachining process, if the processing system can't determine and position the location of the focus image plane, it will be difficult to obtain a higher processing speed and stable processing quality and it is time-consuming,too.The main content of this dissertation included two parts which are how to find the focus image plane position in the excimer laser micro-etching process and Z axis tracking system. This dissertation made a more detailed study and discussion about the excimer laser micro-etching process, Matlab curve fitting theory, laser displacement sensor's working principle and the track-controlling software's implementation.First, this dissertation researched the autofocus research situation of laser processing system at home and abroad, and discussed the research and development direction of autofocus and the problems existing in current laser processing systems; then analyzed the characteristics of the excimer laser micromachining, determined the overall framework of this project for its demand, and carried out the research gradually.Secondly, starting from the excimer laser micromachining system existing in our laboratory and according to the motion characteristics of the micro-machining station, this dissertation proposed using Matlab curve fitting method in order to achieve determining the position of the focus image plane in the etching process, made detailed analytical study of Matlab curve fitting theory; studied the working principle of laser displacement sensors deeply at the same time, and built a Z axis tracking system with a laser displacement and a six-dimension electric station which controlled by a computer in order to achieve tracking Z axis.Finally, using Windows as the operating platform and Microsoft Visual Basic as the developing software, this dissertation established an etched images information database which etched by the excimer laser processing, developed a program of the Z axis tracking control software, carried out the focus image plane positioning and Z axis tracking experiments simultaneously and achieved the requirements of the whole system.